Gastric teratoma is a very rare, usually benign, tumour of childhood. In industrialized countries, the diagnosis is facilitated by advanced technology when the infant is still in utero or soon after birth, and surgery is performed quite early in life, long before symptoms appear. This tumour was seen in our hospital in a 4-month-old boy. A mass had been noted at birth, but the infant remained symptomless. He was brought to hospital only on account of its rapid growth. The teratoma was successfully excised and the child was not seen again after discharge from hospital. We presume he remains well.